Steam-engine.



W. M. WILKIN.

STEAM ENGINE.

APPLICATION men NOV. 19, 1914. RENEWED JULY 7 I916.

Patented Feb. 6, 191?.

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Warmer: M. wrnmn', or am, PENNSYLVANIA.

smart-Enema.

Application filed November 19, 1914, Serial No. 872,981.

To all whom it may concern;

Be it known that I, WILLIAM M. 'WILIIKIN,

to the accompanying drawings, and to the letters of reference marked thereon, forming part of this specification.

y invention relates to steam engines and particularly to that type of steam engine known as central exhaust engines.

The object of my invention is to so construct a central exhaust engine with comparatively light piston mechanism, and to provide an exhaust'cha-mber within the cylinder from which the used steam may escape continuously during the'operationof the engine.

In carrying out these objects, I provide an engine cylinder with a deep circumferential groove in the central part of the interior wall thereof, and with longitudinal grooves of less depth extending from said circumferential groove toward each end of said cylinder, and with the usual steam inlet ports at each end of'said cylinder, and upon the piston-rod I secure two comparatively light pistons each of which in its reciprocadE'F tions is adapted to travel over the longitudinal grooves and slightly past the edges of said circumferential groove, so that the space between said pistons ,will at all times open directly into said circumferential groove.

These and other features of my invention will appear hereinafter in the specification and claims, and are illustrated in the accompanying drawings, in which:

igure 1, is a longitudinal central section a steam engine embodying my invention. Fig. 2, is a transverse section of the same on the line m-m in Fig. 1, looking in the direction of the arrow. I

In these drawings A, indicates an engine cylinder, and B B, indicate pistons therein secured in tandem upon a piston-rod C; C and C indicate cylinder heads closing the ends of the cylinder A; D and D, indicate valve chests, which communicate with the cylinder A, through the steam ports a and Specification of Letters Patent.

such as will enable others skilled in the art to which it appertains to make and use the same, reference being had Patented Feb. 8, 119W. Renewed July 7, 1916. Serial No. 108,056.

a; and d and 03 indicate valves in said valve-chests adapted to control said steamports'a and a"; E, indicates the valve-rodto which the valves d and d, are attached, and Which-is adapted to be actuated by some moving part of the engine in the usual way indicates a to operate said valves. E, steam-pipe leading from the throttle-valve E to-each valve-chest D and D.

Around the central part of the cylinder A, I provide an exhaust passage F, which communicates with the exhaust-pipe F. In

the interior surface of the cylinder A, I provlde grooves G, in Qspaced relation to each other and which extend longitudinally from each side of the exhaust-passage F, toward each cylinder-head and are of greater length than the width of the pistons said pistons will, at the end of each stroke thereof, uncover the ends of the grooves G, nearest' to that cylinder head which is farthest away from said pistons,

In operation, Fig. 1, shows the piston B, as having opened the grooves G, on its side of the passage F, to permit steam to exhaust through said grooves into the passage F, and also into the space between the two pistons B and B, from which space it can continue to flow out through the passage F, and pipe F, while steam is admitted through the steam-port a, and the piston B, is drlvlng both pistons on the return stroke toward the I head (1?. When the piston B, uncovers the grooves .G, on its side of the passage F, the exhaust operation is repeated. It Wlll thus be seen that the pistons B and B, never close communication betweenthe space be; tween the pistons B, and the passage F, and that there will be a continuous flow of exhaust steam therefrom.

. To relieve the compression incident to the return of the pistons B B, toward the1r respective cylinder-heads C and G I provlde valves H H, in each of said pistons, and connect said valves by a rod H so that the pressure behind the piston B, either from compression or incoining steam, W111 close the valve II, in the piston B, and through the rod H open the valve H, in the piston B, in which position said valves will remain until the pressure behind the piston B reverses saidvalves.

It will therefore be seen that by means of the construction hereinbefore described, I

am enabled to dispse with a piston of a B B, so that of the cylinder, and to employ inits stead two comparatively light pistons, thereby saving the power unnecessarily consumed in driving the excess weight; also by utilizing the space between the pistons as an exhaust chamber, I eliminate such back pressure as may be incident to the crowding of the entire volume of the exhaust steam immediately into the chamber F, and pipe F, the

volume of exhaust being continuous from the space between the pistons B B.

Therefore having fully described the construction and operation of my invention so as to enable others to utilize the same, what I claim as new and desire to secure by Letters-Patent, is

1. The combination in a steam engine of a cylinder having its interior wearing surface cut-away at a point co-incident with termination of the forward stroke of the piston, and longitudinal grooves in said wearing surface, extending from said point toward the head of said'cylinder, and a piston in said cylinder adapted'to reciprocate between the head of said cylinder and the "point where said wearing surface is cut away, whereby steam may be allowed to ex haust through said longitudinal grooves, substantially as set forth. a

2. The combination in a steam engine of a cylinder having its interior wearing surface divided at the central portion by an annular groove therein, and having longitudinal exhaust grooves in said interior surface extending from said annular groove toward the heads thereof, steam ports at the ends of said cylinder, a piston rod in said cylinder, a pair of pistons on said rod so spaced thereon that .each will uncover theends of said exhaust grooves nearest the cylinder heads, but not pass said annular groove, whereby steam will be permitted to exhaust through said longitudinal grooves, a non-return valve in each of said pistons, a rod connecting said valves so that when one of said valves is opened, the other will be closed, whereby compression between said pistons and the cylinder heads may be relieved, and means 1 to control \the admission of steam to said cylinder, substantially as set forth.

3. The combination in a steam engine of a cylinder having steam inlet ports at the ends thereof and exhaust passages at the intermediate portion thereof, a piston rod there- 'in, a pair of pistons so spaced on said rod WILLIAM M. WILKIN.

Witnesses P. V. BIFFORD, W. R. WILK N. 

